This invention relates to sliver forming devices, and more particularly to a special type of pneumatic condenser which is mounted at the output of a carding machine or the like, and which utilizes air flow for separating a fiber web directly into a plurality of separate slivers or rovings.
In the production of yarns it is customary to separate a wound woven web, which is doffed from a carding machine or the like, into a plurality of separate, narrow ribbons or bands. These bands are then manipulated manually or by a number of mechanical devices to form a rope of material which is then passed into a trumpet and draft roller assembly to produce a product which is generally referred to as a sliver or roving.
Most forty inch wide carding machines used in the cotton industry produce a single sliver per machine. Although some can produce two slivers, it is very rare that more than two slivers are made from a single machine. In the woolen industry, however, where wider machines are employed, a number of ribbons or slivers are made by the use of a ribbon condenser which cuts the web structure (via small belts) into continuous ribbons, which are turned into woolen yarn, etc.
U.S. Pat. No. 3,018,521 discloses one type of strand forming apparatus heretofore employed for separating a fiber web into a plurality of spaced, parallel strands by conveying the web on a screen conveyor over a series of axially spaced rings, which rotate coaxially about a fluid dispensing plenum. Fluid under pressure is forced radially outwardly between the rings thereby separating the web into a plurality of spaced, parallel strands. The disadvantage of this apparatus is that it is designed to supplement the conventional web forming condenser and is not designed substantially simultaneously to form a web and in the same operation to roll its fibers into one or more slivers. Furthermore, as a practical matter, the apparatus disclosed by this patent requires that a liquid be dispensed from the plenum in order to retain the fibers in their strand or sliver forms.
Two other U.S. Pat. Nos. 3,135,023 and 3,230,584 disclose variations of the apparatus taught by the above-noted U.S. Pat. No. 3,018,521 . In certain of these embodiments the separating liquid is forced through a web that overlies, or is placed beneath, a plurality of parallel slots formed between spacer elements, which then cooperate with the dispensed fluid to separate the web into parallel strands. Certain of these embodiments also suggest passing the web over a slotted vacuum box so that the fluid (liquid) under pressure will pass through the web and into the vacuum box through its slots. However, neither of these latter two patents discloses apparatus which is designed to use two separate vacuum sources, one of relative low value for forming the web, and one of relatively high value for separating the web into one or more strands or slivers.
It is an object of this invention, therefore to construct improved sliver forming apparatus, which is capable of simultaneously forming carded fibers into a nonwoven web, and in the same operation forming the web into one or more slivers.
A further object of this invention is to provide a novel condenser construction which is adapted to be mounted at the output of a card successively to form carded fibers into a web, and then to divide the web into one or more slivers in substantially the same operation.
A more specific object of this invention is to provide a novel sliver forming apparatus including a condenser mechanism having both low and high vacuum sources used for successively forming carded fibers into an unwoven web, and then to form the web into one or more slivers.
Other objects will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.